Dental hand piece



May 31, 1949. H. E. T. JENSEN DENTAL HAND PIECE Filed Aug. 21, 1946 6 2;2 E M i l sf J i 1, \K z J1 r a $2 1 5 1 4 a 4 l J 2 E m 9 2 m m 7 l 2 8d z H YN' H a 2 Z 7 2 Z V EN TOR. Mm

Jim 6 v7. /mm

Patented May 31, 1949 UNITED STATES PATENT OFFICE DENTAL HAND PIECE HansE. T. Jensen, Los Angeles, Calif.

Application August 21, 1946, Serial No. 692,010

2 Claims. 1

My invention relates to hand pieces used by dentists for themanipulation of the burrs, or rotary tools, employed in the preparationof cavities in teeth and other drilling and cutting operations and ithas for its object to provide an improved hand piece serving as theconnection between the flexible drive shaft and the tool whereby theangularity of the latter may be adjusted with reference to its holderfor the greater convenience and comfort of the dentist in theperformance of difficult operations and at the same time maintain aperfectly smooth transmission of the power delivered to the tool.

My invention also has for its further object to provide a contra anglehand piece for dental use in which provision is made for the relativeadjustment of the intermeshing gears to effect a smooth transmission ofthe power delivered to the tool, said adjustment facilitatin the initialassembly of the tool, the subsequent take-up required to compensate forwear of the parts, and also to accommodate the proper operation of theparts when changes in the angular position of the tool on the handle aremade from time to time.

A still further object of my invention comprehends the provision of afitting, between the elbow of the hand piece per se of a contra anglehand piece and the angular head which carries the tool or burr, in theway of a threaded neck piece carrying a section of the power shaft andgears, and an adjustable element on the head for the burr carryingsleeve and its driving gear with reference to its intermeshing gearcarried by the aforementioned neck.

To these and other ends my invention embodies further improvements allof which will be fully described in the accompanying specification, thenovel features thereof being set forth in the appended claims.

In the drawings:

Figure 1 is a side elevation partly in section of a dental hand piececonstructed in accordance with my invention.

Figure 2 is an end view showing the angular adjustment of the headrelatively to the hand piece or holder.

Figures 3 and 4 are detail side and top plan views respectively of theelbow portion of the holder.

Figure 5 is a detail view showing in side elevation the neck pieceforming the connecting element between the elbow on the holder and thehead.

Figure 6 is a side elevation of one of the lock nuts used on theconnecting neck piece.

Figure '7 is an enlarged detail in side elevation of the adjustingmember carryin the sleeve in which the burr or tool is removablysecured.

Figure 8 is a bottom plan view of the member shown in Fig. '7 andFigures 9 and 10 are face and side views respectively of the lock nutemployed in connection with the adjusting member shown in Figs. 7 and 8.

Similar reference characters in the several figures indicate similarparts.

A contra angle hand piece embodying my invention comprises a holder orhandle portion l the rear exterior portion of which is provided withknurled annular ridges to facilitate its being grasped in the hand ofthe operator, and a forward elbow portion 2 which is curved, as shown,and is permanently connected to the part I by a threaded connection withthe reduced portion l thereon. These parts are hollow and portion lserves as a journal for the main drive shaft 3, the outer end of whichis adapted to be connected to a suitable source of power such as theusual flexible motor driven shaft, as will be understood. The forwardend of the shaft carries a spur pinion which is embraced by the rear endof the elbow and lies in a central position therein. The rear side ofthe pinion engages the boss l holding the shaft against axial movementin one direction while its movement in the opposite di-- rection isprevented by an annular collar 5 which engages a shoulder within theholder.

The dental tools which are driven by the shaft 3, generally referred toas burrs, of which one is indicated by 6, in Figs. 1 and 2, are carriedin a head 1. In order to provide a readily adjustable connection for thelatter so that the tool may be set at any desired angular position withreference to the handle I I provide special fittings between theseelements.

The forward end of elbow 2 is threaded, as indicated at 8, and the rearside of the head I is provided with a boss which is likewise threaded,as indicated at 9. Between these parts I interpose a neck piece [0 (Fig.5) the extremities of which are provided with threads for uniting theparts 2 and l and are each made of sufiicient length to carry nuts H andI2 (Figs. 1 and 6) which by being tightened against the shoulders formedon the parts serve to lock the neck piece in its adjusted position withrespect to each of them.

As will be seen in Fig. l the threads on the ends of the neck pieceextend thereon toward each other to receive the nuts H-l2 and theproximate ends of the latter are recessed and form sleeves which coverthe end threads at all times.

The neck piece i'z'l carries a transmission shaft it having fixed at itstwo ends spur gears Hi and ill, the former being adapted to mesh withgear 4, at the crook in elbow 2, and the latter engages a similar gearH6, at right angles thereto carried in the head 1 and serving as thedriving element of the hollow spindle which carries the tool 6. Thegears i i and i abut accurately against the end faces of the neck pieceill thus preventing longitudinal movement of shaft l3, hence it will beappreciated that by the longitudinal position or adjustment or the neckpiece It in elbow 2 a very accurate meshin of gears 4 and Hi can beobtained in the first instance and maintained by subsequent adjustment,when necessary. Likewise the gear l5 may be properly positioned withreference to its companion gear 16. The nuts H and 1.2 serveindependently to secure the two ends of neck piece B/Ioreover, byloosening either or both of such nuts the head i may be turned asrequired, either to the right or the left to ob-- tain the desiredangularity or the tool with reference to the handle as shown in Fig. 2.This is accomplished without materially disturbing the pitch engagementof the gears. This is due in fact to the fineness or the threads 8 and 9between which the degree of adjustment may be divided. If desired all ofthis angular adjustment, may be efiected on the threaded connectionbetween the head i and neck piece it) as I have also provided for theseparate independent adjustment of the tool spindle driving gear It, aswill be now explained.

The shank of dental tools, as indicated by 6, are carried in a tubularspindle til, journaled in a recess bored in the head i, which carriesthe spur pinion ll; meshin with gear lll lying in an intersecting boreof the head. The pinion provides a collar on the spindle which ridesupon the inner end of a threaded sleeve 22 (Fig. 7) which also forms ajournal for the lower end of tool spindle 20. Sleeve 22 is adjustable inhead 1 to accurately position the pitch line of the gear teeth on pinionH5 in mesh with that of the teeth on gear l5 and to facilitate itsadjustment by ones fingers I knurl its lower edge as indicated by 23 andshown particularly in Fig. 8. And to securely lock it in position thesleeve carries a nut 26 (Figs. 1, 9 and 10) which engages the rim of thecollar formed on. lower side of head i.

While each of the nuts ll, l2 and 2 3 may be finger operated andprovided with knurled surfaces for this purpose I deem it preferable,because of their small size to give them a polygonal shape which permitsthe use of a wrench for tightenin them. To this end I also provide theelbow 2 of the holder with flattened surfaces 25 on its opposite sidesfor the reception of the jaws ofla spanner wrench, for holding it whileone or the other of the nuts ll and i2 is being set in place.

The head 1 is provided with a slot it which is open at one side andlying therein is the burr latch 21. This is pivoted on a smallshouldered screw 28 so that it may be moved laterally by applying aslight pressure on its free end 29 to engage or disengage its oppositeextremity from the annular groove provided in the shank of the burr ortool 6, as will be understood.

It will be readily appreciated from the arrangement of the parts hereindescribed that I have provided a unique construction of elements capableof being readily assembled in the first instance and subsequentlyadjusted to position the tool carrying head at any desired position withreference to the handle and also adjusted to compensate for wear of anyof the parts, hus preserving a smooth operation between the severalpinions or gears at all times.

What I claim and desire to protect by Letters Patent is:

1. In a dental hand piece the combination with a tubular handle having adrive carrying a. driving pinion, and a head mounted on the handlehaving a bore intersecting the pinion axis and provided at its outer endi an interior thread, of a spindle journaled in said bore carrying apinion meshing with the drive pinion, a sleeve carried by the threadedportion of the head having an inner end en aging the spindle pinion andan outer end extending beyond the head and knurled on its outer end forfinger adjustin engagement and a nut on the projecting end of the sleevecooperating with the head for locking said sleeve.

2. A contra. angle dental hand piece comprising a handle proper providedwith an interior threaded elbow and a drive shaft in the handleoperating a pinion in the elbow, a head piece having a boss at one sidefacing said elbow and interiorly threaded and provided with a tooljournal bore extending at right angles to said boss, a tool spindletherein carrying a pinion, a tubular neck having threads at its oppositeends engaging within those of the elbow and head for uniting them, saidthreads also extending toward each other beyond. said points ofengagement, a transmission shaft in said neck, pinions thereonabuttingthe ends of the heel: arranged for cooperative engagement onewith the drive pinion and one with the spindle pinion the pitchengagement of the several pinions bein adjustably controlled by movementof the sleeve on its threads, nuts on the, exposed portions of saidthreads for independently locking the opposite ends of the sleeve to theelbow and head, said nuts on their proximate ends having recessed endsextending beyond the threads on the neck, the journal bore of the headat its outer end being also threaded, a sleeve carried thereby foradjusting the spindle pinion having an outer knurled and extendingbeyond the head for finger adjusting engagement and a lock nut for saidsleeve bearing against the end of the head.

HANS T. JENSEN.

REFERENCES CETED The following references are of record in the file, of.this patent:

UNITED STATES PATENTS Number Name Date 1,638,175 Terry Aug. 9, 19271,688,136 Chayes et al Oct. 16, 1928 2,025,779 Roellze Dec. 31, 19352,033,662 Witt Mar. 19, 1936 2,360,332 Fosdal -1 Oct. 24:, 1944

